A simple event system | How to?

Question

I want to implement this interface

addListener(name, callback);
removeListener(name, [callback]); // callback is optional
trigger(name);

All events will be triggered on an internal event bus

var bus = {}

that is not part of the interface.

This is the simplest interface I could imagine that is actually useful.

However I still don't how to implement these interfaces conceptually. I've perused the backbone event system , but can't quite understand how they implement this core functionality.

I just want to write a quick 10-100 line event system that is as simple as possible and based upon the more complex Backbone event system.

Answer 1

You could use Backbone.Events module for it.

Stolen shamelessly from lostechies

You could use an Application level event aggregator:

MyApp = {};
MyApp.vent = _.extend({}, Backbone.Events);

MyApp.vent.on("some:event", function(){
  alert("some event was fired!");
});

MyApp.vent.trigger("some:event");

Answer 2

Check out the minimal event bus library minibus.js . It currently has different API but might be exactly what you are looking for.

var bus = Minibus.create();
bus.on(name, callback);  // add listener
bus.emit(name);          // trigger event
bus.off(name);           // remove listener